Bitter is an English term for pale ale, which is a beer and vary in colour from gold to dark amber and in strength from 3% to 7% alcohol by volume. bitter A type of taste a person can feel with their senses.
Chalk is a limestone deposit created as plankton (tiny marine organisms) concentrate calcium in their bodies while living, then leach the calcium out after they die and settle onto ocean floors; over millennia, large deposits are formed, and as the seas recede, chalks deposits remain.
A quadruple blackboard at the Helsinki University of Technology. A blackboard (UK English) or chalkboard (US English; also blackboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulfate or calcium carbonate, known, when used for this purpose, as chalk.